[tor-relays] wild swings in Advertised Bandwidth

[jchase]

Hi,
I'm running a low-volume bridge on a raspberry pi. Globe.torproject says
that my fingerprint is 1BCD3EBEFE17EEB86EEDE21D5E2DB8468E2864CF . I'm
keeping an eye on myself and traffic via globe.torproject and my
advertised bandwidth makes wild swings: one day its 56 kB/s and the next
day it's 8 kB/s. When I read that "The minimum BandwidthRate setting is
20 kilobytes per second", I am confronted with the fact that 8 is less
than 20 and it doesn't seem worth it keeping my bridge up and working.
Why would a bridge make such swings in advertised bandwidth? And is
there any good reason to keep the bridge up and working if it sinks to 8
kB/s?
Thanks,
J Chase